This invention relates to de-icing systems for use with aircraft, particularly those systems employing electromagnetic impulse technology for deforming the airfoil skin of the leading edge or nose portion of the wing and fin members of an aircraft. It is well known that deformation of the airfoil skin can fracture the ice formed thereon during flight and so aid in the ice's break-up and removal from the wing or fin member. This particular kind of technology is to be contrasted with other and earlier stratagies used for similar purposes, such as the Bleed Air type which uses air from the engine to heat the aircraft structure, requiring therefore special ducting systems and extra engine power to deliver the heat, the Thermal type which requires substantial amounts of power for heat, and the Weeping Wing which comprises thousands of tiny holes drilled in the wings through which a chemical bleeds to wet the wings' surfaces with a glycol solution or the like.
In the case of electromagnetic systems, however, British Pat. No. 505,433 provides a basic teaching of employing electromagnetic impulses as a source of wave or mechanical deformation in the skin of an airfoil, as well as generally positioning the force producing electromagnetic coils in the vicinity of the leading edge of the airfoil and, further, sequentially energizing an array of such coils along the long axis of the airfoil. Further examples of energy or pulse producing and distribution systems may be had from the various patents owned by Levin et al, particularly U.S. Pat. No. 3,779,488 which shows more advanced technology, namely, program switching devices for energizing the various coils arranged in the airfoil.
More recently, U.S. Pat. No. 4,399,967 directs its attention to a particular configuration of coil arrangements which employ the prior art concepts above described. More particular, this patent teaches a staggered array of impact coils spanwise of an airfoil so that when the coils are energized a torsional wave deformation occurs in the skin of the airfoil.
With respect to the prior art systems and electromagnetic systems generally, performance is limited by a number of factors including the stress produced in the airfoil, the magnitude of deformation for a given size coil, the weight and physical distribution of such systems throughout the aircraft, the individual coil configuration and support within the airfoil itself, and the nature of the array of the coils within the entire airfoil.